摘要 |
Cephalosporins I (Ra,Rb=Me, Et, n-Pr, n-Bu or makes C3-5 cycloalkylidene group with C;R1=C1-4 alkyl) were prepared by acylating compd. II (B=S or SO) with acylating agent (III, R2=carboxyl protecting group) or by reacting IV (R4,R4a=H, carboxyl protecting group) with alkylpyrazole(V), or by reacting VI with R'-introducing alkylating agent. Thus, depheylmethyl(1S,6R,7R)-3-bromomethyl-7-≮(z)-2-(2-t-butoxycarbonyl prop-2-oxyimino)-2-(2-tritylaminothiazol-4-yl) acetamido≉ceph-3- em-4-carboxylate, 1-oxide was prepd. from (z)-2-(2-t- butoxycarnonylprop-2-oxyimino)-2-(2-tritylamino-thiazol-4-yl)acetic acid as starting material. |